THE WOODLANDS, TEXAS — According to planetary scientist Carver Bierson, a young and ultrabright Jupiter may have caused the desiccation of its now hellish moon Io. Bierson reported at the Lunar and Planetary Science Conference on March 17 that the planet’s bygone brilliance could have also vaporized water on Europa and Ganymede. If this is true, it could help researchers narrow the search for icy exomoons by eliminating unlikely orbits.
It is believed that the radiance would have been inescapable for the giant planet’s moons, which include volcanic Io, ice-shelled Europa, aurora-cowled Ganymede, and crater-laden Callisto. The constitutions of these four bodies obey a trend: the more distant the moon from Jupiter, the more ice-rich its body is.
Bierson and his colleagues hypothesized that this pattern was a legacy of Jupiter’s past radiance. The team used computers to simulate how an infant Jupiter may have warmed its moons, starting with Io, the closest of the four. During its first few million years, Io’s surface temperature may have exceeded 26° Celsius under Jupiter’s glow, Bierson said. “That’s Earthlike temperatures.”
Any ice present on Io at that time, roughly 4.5 billion years ago, probably would have melted into an ocean. That water would have progressively evaporated into an atmosphere. And that atmosphere, hardly restrained by the moon’s weak gravity, would have readily escaped into space. In just a few million years, Io could have lost as much water as Ganymede may hold today, which may be more than 25 times the amount in Earth’s oceans.
2023-03-28 07:00:00
Original from www.sciencenews.org